I hate to be predictable but to be honest, what other film ranks higher than The Avengers? The Avengers not only is one of the most successful comic-book films of all-time but the pinnacle of what modern-day franchises strive for. Ever since Marvel successfully pulled-off the cinematic universe idea, studios have strived to find which properties they can merge together in order to set-up a film where everyone comes together for one major event. Warner Brothers tried that with Justice League and failed. Universal has tried to get their "Dark Universe" off the ground but the failure of The Mummy might have killed that franchise on arrival. The only cinematic universe that seems to have some success going is Legendary's Monster Universe involving King Kong and Godzilla. That being said, Avengers is up here not only because it is widely considered the bet comic book film of all time. While being the one of the best comic book films of all times is a major feat, the larger fact is that The Avengers changed the way studios make films now.
While studios like Warner Brothers and Paramount owned large properties such as DC Comics and Hasbro, they never considered crossing over their characters. While WB always toyed with the idea of a Batman/Superman film after the success of Tim Burton's run at the character, it still took over 25 years to bring those two characters together on the big screen. There is a lot of work that goes into producing cross-over films. Marvel Studios is the one and only studio that has truly made a cinematic universe work. Say what you will about the DCEU or other universes out there, Marvel has stuck to their ideas on how they build their worlds. The Avengers also had the best MCU villain for the longest time. How Whedon and company crafted and expanded the ideology of Loki in this film is impressive. While Loki was far from being a weak character in Thor, the evolution of his character within this film set the bar for future antagonist to come, for better or for worse. We will see if Thanos in Avengers: Infinity War can live up to his billing.
Well now that this list has concluded, the story turns to what the future holds for the MCU. Are the brightest days of this franchise behind us or ahead of us? While that question is not easy to visualize yet, there are two things that are certain with the future of the MCU. One is that Marvel is aware of their villain crutch and they're aggressively changing the tone of that criticism. Since the release of Spider-Man: Homecoming, Marvel has had great responses to their new wave of villains including Vulture, Hela, and Killmonger. If Thanos knocks it out of the park, four of the top five MCU villains could be from the last wave of MCU films.
The other initiative that Marvel is putting on their films is making their properties interconnect more. While Marvel films have had Easter eggs and quick cameos in the past, you could easily skip Thor's solo film or the Guardians of the Galaxy newest volume and now miss any important information regarding your favorite heroes. Now, Marvel seems to be changing tones by placing a lot of knowledge from prior films into future films. While fans of the franchise will enjoy these rewarding moments, newcomers and regular fans of the franchise might begin to feel like their missing something and begin to feel disconnect with the MCU. Whether these decisions harms or helps the franchise remains to be seen but until they're proven wrong, let Marvel go do their thing.